A lathe power chuck typically has a body with three slots which are offset by 120 degrees from one another. Each slot contains a master jaw which moves radially inward and outward in unison with the others. A replaceable top jaw mounts to each master jaw for moving inward to grip a workpiece. The top jaws have malleable inserts mounted to them which engage the workpiece. Although inserts can be purchased, a machinist may wish to fabricate inserts using a lathe. While this method is feasible, a more convenient means is needed.